The END OUT output should be clamped to 5V because there is a zener diode in
that line. If that is the output you are having problems with then the zener
is either faulty, not fitted, or the wrong value.
The OUT output doesn't have any such protection and it is feasible for the
output to approach power rail levels as it is driven directly from the
output of an opamp. I will need to study the front end more to determine if
there is any internal clamping but it might be worth asking Ken what are the
normal output levels to be expected. Maybe this output needs a simple
resistor divider.
The transistors are standard and should fit the pcb as is.
The only other problem I can see is that Ken has 4 x 220K listed in his BOM
and then says in the text that they should be 22K. I have supplied 220K
Best Regards
Laurie Biddulph
Mobile: 0400 257 645
Web: www.elby-designs.com
-----Original Message-----
From: cgs_synth@yahoogroups.com [mailto:cgs_synth@yahoogroups.com] On Behalf
Of scozbort
Sent: Friday, 23 September 2011 6:43 AM
To: cgs_synth@yahoogroups.com
Subject: [cgs_synth] Re: cgs75 hot voltage outputs
OK here is some more info.
Most people seem to have difficulty with the transistor pin-outs not
matching the circuit. I don't think this is the problem here. The module
functions perfectly (except for hot output), and the transistors were
supplied in an Elby kit. I have emailed Laurie to see if the transistors he
supplied are correct (can't seem to find a datasheet for them).
Also the calibration trimmer does offset the hot output voltage, but no
where near enough. I was wondering if a 20 turn trimmer here would allow me
to drop the voltage of the output right down whilst still maintaining the
correct triangular waveshape?
Like I said it only outputs high voltages when its being triggered.
It's completely useful as it is, I just have to attenuate the output. Not
comfortable send 15v signals around the modular. Or do I not need to worry
about this at all? I know it distorts my VCAs pretty quick.
Any help much appreciated!
- Kevin
that line. If that is the output you are having problems with then the zener
is either faulty, not fitted, or the wrong value.
The OUT output doesn't have any such protection and it is feasible for the
output to approach power rail levels as it is driven directly from the
output of an opamp. I will need to study the front end more to determine if
there is any internal clamping but it might be worth asking Ken what are the
normal output levels to be expected. Maybe this output needs a simple
resistor divider.
The transistors are standard and should fit the pcb as is.
The only other problem I can see is that Ken has 4 x 220K listed in his BOM
and then says in the text that they should be 22K. I have supplied 220K
Best Regards
Laurie Biddulph
Mobile: 0400 257 645
Web: www.elby-designs.com
-----Original Message-----
From: cgs_synth@yahoogroups.com [mailto:cgs_synth@yahoogroups.com] On Behalf
Of scozbort
Sent: Friday, 23 September 2011 6:43 AM
To: cgs_synth@yahoogroups.com
Subject: [cgs_synth] Re: cgs75 hot voltage outputs
OK here is some more info.
Most people seem to have difficulty with the transistor pin-outs not
matching the circuit. I don't think this is the problem here. The module
functions perfectly (except for hot output), and the transistors were
supplied in an Elby kit. I have emailed Laurie to see if the transistors he
supplied are correct (can't seem to find a datasheet for them).
Also the calibration trimmer does offset the hot output voltage, but no
where near enough. I was wondering if a 20 turn trimmer here would allow me
to drop the voltage of the output right down whilst still maintaining the
correct triangular waveshape?
Like I said it only outputs high voltages when its being triggered.
It's completely useful as it is, I just have to attenuate the output. Not
comfortable send 15v signals around the modular. Or do I not need to worry
about this at all? I know it distorts my VCAs pretty quick.
Any help much appreciated!
- Kevin
--- In cgs_synth@yahoogroups.com, "scozbort" <kevin.babbage@...> wrote:
>
> Hi!
>
> Can't believe I only just found this place...
>
> I'm having an issue with my VCS build and hoping someone has come across
it before.
>
> When I use the trigger in and slow fall times the module outputs very hot
voltages - I think it would go to 15v if I let it.
>
> But in cycle mode it outputs normal voltages.
>
> I suspect a wiring fault but I can't see any mistakes, unless of course I
have misunderstood how to wire it up - which is likely!
>
> Hoping its an easy fix and thanks in advance
> - Kevin
>
------------------------------------
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